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    <title>Document</title>
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    <script>
        //利用递归函数求1~n的阶乘 4! = 1*2*3*4
        var mul = 1;
        for(var i = 1;i<=10;){
            mul*=i;
            i++;
        }
        console.log(mul);

        function fn(n){
            if(n == 1)
            {
                return 1;
            }
            return n*fn(n-1);
        }

        console.log(fn(10));
        console.log(fn(5));
    </script>
</body>
</html>